Damien Wood, QMI Agency

CALGARY -- The mother of a young Calgary man killed fighting alongside Islamic extremists had heard rumours of a pair of Calgary brothers who'd gone over about the same time.

Christianne Boudreau doesn't know if that pair are Collin and Gregory Gordon -- first reported by CBC Thursday as being the latest two confirmed to have joined ranks with the Islamic State of Iraq and Syria (ISIS) -- but the timing fits.

"I'd heard months ago that there were two brothers that were gone," she said. "I've just heard rumours. There were stories going around (then) that there were two brothers that went about a month apart."

CBC broke the story Thursday, identifying the Gordon brothers as having once lived in the same downtown Calgary highrise as Boudreau's son, 22-year-old Damian Clairmont.

And like Clairmont and others, Collin and Gregory Gordon reportedly disappeared sometime late 2012.

Collin is active on social media, under both his given name on Facebook and, reportedly, the monicker Abu Ibrahim Canadi on Twitter where one post refers to the recent slaying of an American journalist.

"10/10. The video of James Foley losing his neck is the perfection of 'Terrorism'." the post reads.